CroftSoft / Library / Tutorials

Open Source License Comparison

David Wallace Croft



Licensee Requirements PD AFL CPL LGPL OSL GPL
Maintain Attribution and Disclaimer N Y Y Y Y Y
Must Distribute Modified Source N N Y Y Y Y
Same License for Larger Work N N N N Y Y

Licenses are sorted in the chart by requirements imposed upon the licensee. Requirements imposed upon the licensor, such as a requirement to grant licensee patent permissions, are not considered.

PD Public Domain (technically not a license)
AFL Academic Free License (replaces Apache, BSD, and MIT)
CPL Common Public License (akin to LGPL?)
LGPL GNU Lesser General Public License (a.k.a. Library GPL)
OSL Open Software License (akin to GPL?)
GPL GNU General Public License (most popular)

Only generic Open Source licenses were considered in the comparison. This excluded licenses such as the Apple Public Source License (APSL) and the Jabber Open Source License (JOSL). I prefer generic Open Source licenses because I can adopt them without needing to customize them and risk accidental oversights of needed text substitutions.

Other Open Source licenses have been excluded because I believe that they have been superannuated by modern licenses such as the AFL, CPL, and the OSL. The GPL and LGPL may fit into this category but I included them because they are widely used.

The CPL is an interesting choice. It requires that the licensee share and distribute any modifications to the licensed Open Source code. On the other hand, it is non-viral in that does not require that a larger derivative work that incorporates this modified Open Source code also be distributed as Open Source. In these respects, it is like the LGPL. In my opinion, the main flaw with the CPL is that it may be modified at any time by IBM and all source code released under earlier versions of the CPL would be affected by the change. For this reason, I have abandoned the CPL in favor of the AFL.

If there is a licensee requirement comparison feature or generic Open Source license that I should have considered but did not, please let me know.


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